Isolation arrangement for system under test

ABSTRACT

An arrangement for isolating an energy transfer system while it is subjected to a test process for noise. The energy transfer system is of the type having an energy input and at least one energy output, and may be mechanical or electrical. The isolation arrangement has a base that supports the energy transfer system. An isolation support supporting the energy transfer system, yet affords multiple degrees of freedom with respect to the base. The energy transfer system is clamped in a manner that permits the multiple degrees of freedom with respect to the base, via an engagement arrangement that secures the energy transfer system to the isolation support. The engagement arrangement has a first position with respect to the base wherein the energy transfer system is installable on, and removable from, the isolation support, and a second position wherein the energy transfer system is secured to the isolation support means. Engagement is effected by an actuation element that is effectively decoupled from the base after clamping is achieved. In a mechanical embodiment, rotatory energy is provided to the energy transfer system exclusively as torque, without any significant axial bias. Additionally, processes for signal analysis enable “pass/fail” determinations to be made with respect to noisiness of the system under test, as well as the presence of bumps and nicks in gear systems under test.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to systems for testing electrical andmechanical energy transfer systems that exhibit vibratory and otherresponses to electrical or mechanical input energy, and moreparticularly, to an arrangement that isolates a mechanical or electricalsystem under test and produces signals and data corresponding to aplurality of operating characteristics of the system under test inresponse to the input energy.

2. Description of the Related Art

Noise testing of gears to date has been attempted by methods thatrigidly mount the gear or axle assemblies in one or more planes. Someother previous attempts chose to have one of the rigidly mounted planesresonate at a frequency sympathetic to gear noise. None of thesemethods, or any other rigidly mounted test system has been successful.This is due to the lack of repeatability of the previous systems,largely as a result of interacting resonances, and external backgroundnoise that is transferred through the rigid mounting system. This isespecially true in a production test environment.

These deficiencies in the prior art are most evident in the axleindustry. At this time, the only widely accepted way of measuring gearnoise is to acquire an assembled axle and install it in a test car. Aspecially trained individual then drives the car over its typicaloperating range while carefully listening for axle gear noise. Theindividual rates the quality of axle gear noise on a scale that istypically 0 to 10. Ten is usually a perfect axle, i.e. one that has nogear noise. This method is made difficult by:

1 The lack of available trained noise rating individuals

2 The cost of test cars.

3 The lack of quality roads or test tracks on which to perform arepeatable and accurate test.

4 The time required for each test.

5 The subjectivity that humans bring into the rating system

Typically less than a dozen axles can be tested by a major manufacturerin one shift due to all of the above complications. This low number isnot statistically valid when it is considered that most manufacturersmake thousands of axles each day. Even with all of the above problems,human testers in cars are the only widely accepted method of axletesting in the industry due to the lack of a better more reliabletesting method. This lack of a scientific basis for rating axles andgear systems is made worse when the reader considers that modern carsare extremely quiet, and are evolving to become more quite. This marketdirection increases the pressure on axle and other gear manufacturers tomake their products quieter. There is a need for a system that offersgear and axle manufacturers a repeatable, reliable, accurate andpractical way of measuring gear noise in production or laboratoryenvironments.

It is, therefore, an object of this invention to provide a system fortesting an energy transfer system, such as a vehicle axle, quickly andinexpensively, and achieving repeatable results.

SUMMARY OF THE INVENTION

The foregoing and other objects are achieved by this invention whichprovides, in a first apparatus aspect thereof, an arrangement forisolating an energy transfer system while it is subjected to a testprocess for noise, the energy transfer system being of the type havingan energy input and at least one energy output. In accordance with theinvention, the arrangement is provided with a base for supporting thearrangement and the energy transfer system. An isolation supportsupports the energy transfer system whereby the energy transfer systemis translatable in at least one plane of freedom with respect to thebase. Additionally, an engagement arrangement is provided for securingthe energy transfer system to the isolation support, the engagementarrangement having a first position with respect to the base wherein theenergy transfer system is installable on, and removable from, theisolation support, and a second position wherein the energy transfersystem is secured to the isolation support.

In one embodiment, there is further provided an energy supply coupled tothe energy transfer system for supplying energy thereto when theengagement arrangement is in the second position. The energy transfersystem is, in one embodiment of the arrangement of the presentinvention, a mechanical energy transfer system, and in such anembodiment, the energy supply, which is a part of the arrangement of theinvention, is in the form of a source of rotatory mechanical energy. Arotatory coupler couples the source of rotatory mechanical energy to theenergy transfer system.

In a highly advantageous embodiment of the invention, the mechanicalenergy transfer system test has forward and reverse directions ofoperation, and drive and coast modes of operation for each of theforward and reverse directions of operation. The mechanical energytransfer system contains at least a pair of meshed elements, at leastone of the pair of meshed elements being a gear having a plurality ofgear teeth thereon, the gear teeth each having first and second geartooth surfaces for communicating with the other element of the pair ofmeshed elements. A mechanical energy transfer communication between thepair of meshed elements is effected primarily via the respective firstgear tooth surfaces during forward-drive and reverse-coast modes ofoperation, and primarily via the respective second gear tooth surfacesduring forward-coast and reverse-drive modes of operation. With such asystem under test, the arrangement of the present invention is providedwith a first acoustic sensor arranged at a first location in thevicinity of the mechanical energy transfer system for producing a firstsignal that is responsive substantially to a qualitative condition ofthe first gear tooth surfaces. A second acoustic sensor is arranged at asecond location in the vicinity of the mechanical energy transfersystem, and produces a second signal that is responsive substantially toa qualitative condition of the second gear tooth surfaces. The first andsecond locations are distal from each other on opposite sides of thepair of meshed elements.

In a further embodiment of the invention, the rotatory coupler isprovided with a resilient coupler arrangement that transmits rotatorymotion there across over a predetermined range of rotatory motiontransmission angles. The resilient coupler arrangement is provided withfirst and second coupler portions, the first and second coupler portionsbeing rigidly coupled rotationally to each other. Additionally, they areaxially resiliently coupled to each other, whereby the first and secondcoupler portions are synchronously rotatable over the predeterminedrange of rotatory motion transmission angles.

In yet a further embodiment of the invention, the resilient couplerarrangement is provided with first and second coupler portions, thefirst and second coupler portions being rigidly coupled rotationally toeach other, and radially resiliently coupled to each other. Thus, thefirst and second coupler portions are synchronously rotatable over apredetermined range of axial displacement.

A torque sensor advantageously is interposed, in a highly advantageousembodiment, between the source of rotatory mechanical energy and theenergy transfer system. The torque sensor produces a signal that isresponsive to a torque applied by the source of rotatory mechanicalenergy to the energy transfer system. The torque sensor is provided witha torque-transmitting element that has a predetermined deformationcharacteristic. Thus, the torque-transmitting element becomes deformedin response to the torque that is applied by the source of rotatorymechanical energy to the energy transfer system. In this embodiment ofthe invention, the torque sensor further is provided with a strainsensor that is coupled to the torque-transmitting element for producinga strain signal responsive to the predetermined deformationcharacteristic of the torque-transmitting element. The strain signal,therefore, is proportional to the torque.

It is very advantageous to determine the residual torque required toinitiate motion of the system under test. The torque sensor is thereforearranged to produce a static torque signal that is responsive to themagnitude of the torque required to initiate rotatory motion in themechanical energy transfer system. In addition, it is advantageous thatthe torque sensor be arranged to produce a dynamic torque signal that isresponsive to the magnitude of torque required to maintain rotatorymotion in the mechanical energy transfer system.

In a particularly advantageous embodiment of the invention, the energytransfer system under test is an electrical energy transfer system, andthe energy supply is provided with a source of electrical energy. Insuch an embodiment, there is provided an electrical load for receivingan output electrical energy from the energy transfer system when theengagement arrangement is in the second position. A first sensor isarranged to communicate with the energy transfer system for producing aninformation signal that is responsive to an operating characteristic ofthe energy transfer system in response to the energy supplied by theenergy supply. The first sensor is arranged to contact the energytransfer system to produce the signal. Alternatively, the first sensoris arranged to contact the isolation support for producing theinformation signal.

The first sensor is arranged, in one embodiment of the invention, so asto be translatable relative to the energy transfer system.

When it is desired to monitor an acoustic energy emitted by the systemunder test, a microphone is provided for producing a signal that isresponsive to an acoustic energy issued by the energy transfer system inresponse to the energy supplied by the energy supply. A laser sensor mayadditionally be provided for producing a signal that is responsive to adisplacement of the energy transfer system in response to the energysupplied by the energy supply. In still further embodiments, anaccelerometer or a velocity sensor is employed.

The resilient support element that supports the energy transfer system,in a preferred embodiment of the invention, is configured to exclude anatural frequency of any combination of the base, the engagementarrangement, and the energy transfer system. Thus, the vibratory oracoustic energy provided by the system under test constitutes all of theenergy that would be measured and analyzed, without contribution ormodification thereof by the structure of the support system.

Preferably, the isolation support supports the energy transfer system sothat it is translatable in at least a second plane of freedom withrespect to the base.

In a highly advantageous embodiment of the invention, there is providedan engagement driver that has a first portion that is coupled to thebase, and a second end that is coupled to the engagement arrangement.The engagement driver is, in one embodiment, provided in the form of alinear actuator that has a first end coupled to the base, and a secondend coupled to the engagement arrangement. The linear actuator isarranged to drive the engagement arrangement between the first andsecond positions. Moreover, it is decoupled from the engagementarrangement when the engagement arrangement is in the second position.

In this arrangement, an engagement coupler is interposed between theengagement arrangement and the engagement driver. The engagement coupleris provided with a support portion installed on the isolation support.First and second engagement arms are pivotally coupled to the supportportion. Additionally, first and second articulated members coupled at apivot point to one another and to the engagement driver, and arepivotally coupled at distal ends thereof to respective ones of the firstand second engagement arms. In this manner, the engagement driver urgesthe pivot point along a predetermined path to a latching position beyondwhere the first and second articulated members are axially parallel.Such a latching effect is facilitated by a resilient biasing arrangementthat is installed on at least one of the first and second engagementarms. The resilient biasing arrangement applies a resilient biasingforce to the energy transfer system, which additionally maintains theengagement arrangement in the second position.

A displacement sensor is installed on at least one of the first andsecond engagement arms, and serves to produce a distance signal that isresponsive to a distance between the one of the first and secondengagement arms on which the displacement sensor is installed and theenergy transfer system. In this manner, the distance signal isresponsive to a predetermined dimension of the energy transfer system.

In a further embodiment, there is provided a thermal sensor forproducing a thermal signal that is responsive to a temperature of theenergy transfer system. The thermal sensor may be in the form of aninfrared sensor that communicates optically with the energy transfersystem. In one specific illustrative embodiment of the invention, thethermal sensor means has a directional characteristic and is directed toa predetermined region of the energy transfer system for determining arate of change of temperature of the predetermined region with respectto time. In this embodiment, there is provided an acoustic sensorsensitivity control arrangement that is responsive to the thermal sensorfor varying the amplitude of a noise signal in response to temperature.The variation of the amplitude of the noise signal with respect totemperature is performed in accordance with a non-linearamplitude-temperature relationship.

In accordance with a further apparatus aspect of the invention, there isprovided an arrangement for isolating a mechanical drive system for avehicle while it is subjected to a testing process, the drive systembeing of the type having a rotatory input and at least one rotatoryoutput. IN accordance with the invention, the arrangement is providedwith a base for supporting the arrangement and the mechanical drivesystem. An isolation support supports the mechanical drive systemwhereby the mechanical drive system is translatable in at least oneplane of freedom with respect to the base. An engagement arrangementsecures the mechanical drive system to the isolation support, theengagement arrangement having a first position with respect to the basewherein the mechanical drive system is installable on, and removablefrom, the isolation support, and a second position wherein themechanical drive system is secured to the isolation support. Anengagement driver is coupled to the base and to the engagementarrangement for urging the engagement arrangement between the first andsecond positions. The engagement arrangement is coupled to theengagement driver when the engagement arrangement is in the firstposition, and isolated from the engagement driver when the engagementarrangement is in the second position. In addition, a rotatory driveapplies a rotatory drive force to the mechanical drive system, and adrive coupler transmits a torque from the rotatory drive to the rotatoryinput of the mechanical drive system.

In one embodiment of this further apparatus aspect of the invention,there is further provided a torque sensor interposed between therotatory drive and the mechanical drive system. The torque sensorproduces a signal that is responsive to a torque applied by the rotatorydrive to the mechanical drive system. Preferably, the torque sensor isarranged to produce a static torque signal that is responsive to themagnitude of torque required to initiate rotatory motion in themechanical drive system. Additionally, the torque sensor produces adynamic torque signal that is responsive to the magnitude of torquerequired to maintain rotatory motion in the mechanical drive system.

In a further embodiment of the invention, the torque sensor is providedwith a torque-transmitting element that has a predetermined deformationcharacteristic. The torque-transmitting element becomes deformed inresponse to the torque applied by the rotatory drive system to themechanical drive system. A strain sensor is coupled to thetorque-transmitting element to produce a strain signal that isresponsive to the predetermined deformation characteristic of thetorque-transmitting element, and consequently, the applied torque.

In a further embodiment, there is provided a sensor that is arranged tocommunicate with the mechanical drive system for producing aninformation signal that is responsive to an operating characteristic ofthe mechanical drive system in response to the rotatory drive force. Afurther sensor communicates with the mechanical drive system forproducing a further information signal that is responsive to a furtheroperating characteristic of the mechanical drive system in response tothe rotatory drive force. The operating characteristic and the furtheroperating characteristic of the mechanical drive system correspond, in ahighly advantageous embodiment of the invention, to drive and coastoperating modes in response to a direction of torque of the rotatorydrive force. As previously stated, the sensor in one embodiment isarranged to be translatable between a first position distal from themechanical drive system, and a second position where the sensorcommunicates with the mechanical drive system.

In this further apparatus aspect, the sensor may be provided with amicrophone that is responsive to an acoustic energy issued by themechanical drive system in response to the rotatory drive force. Inother embodiment, the sensor is provided with an accelerometer, or witha velocity sensor. In other embodiments, the sensor is installed on theengagement arrangement, and is translatable therewith between therespective first and second positions.

In some arrangements, the sensor is a non-contact sensor that produces adisplacement signal that is responsive to displacement of the mechanicaldrive system in response to the rotatory drive force. Such a non-contactsensor may be a laser sensor for communicating optically with themechanical drive system. Additionally, the non-contact sensor produces athermal signal that is responsive to a temperature of the mechanicaldrive system, such as an infrared sensor that communicates opticallywith the mechanical drive system. As previously noted, in one specificillustrative embodiment of the invention, the thermal sensor means has adirectional characteristic and is directed to a predetermined region ofthe energy transfer system for determining a rate of change oftemperature of the predetermined region with respect to time. In thisembodiment, there is provided an acoustic sensor sensitivity controlarrangement that is responsive to the thermal sensor for varying theamplitude of a noise signal in response to temperature. The variation ofthe amplitude of the noise signal with respect to temperature isperformed in accordance with a non-linear amplitude-temperaturerelationship. The variation in temperature over time is useful toindicate low lubricant level, low lubricant quality, or low bearingquality.

In a further embodiment, the isolation support is provided with aresilient support element for supporting the mechanical drive system,and is provided with a resilience frequency characteristic that excludesa natural frequency of the mechanical drive system. Additionally, theresilience frequency characteristic of the resilient support elementexcludes a natural frequency of the drive coupler.

In a mechanical embodiment of the invention. there are additionallyprovided a rotatory load for applying a rotatory load to the mechanicaldrive system, and a load coupler for coupling the rotatory load to therotatory input of the mechanical drive system. The mechanical drivesystem is in the form of a drive-transmitting component for a motorvehicle. In such an embodiment, the rotatory load applies a controllablerotatory load thereto to simulate a plurality of vehicle operatingconditions. These include, for example, gear drive and coast conditions,as well as a gear float condition.

The engagement driver is provided, in one embodiment, with a linearactuator that has a first end coupled to the base, and a second endcoupled to the engagement arrangement. An engagement coupler isinterposed between the engagement arrangement and the engagement driver.The engagement coupler is provided with a support portion installed onthe isolation support, and first and second engagement arms pivotallycoupled to the support portion. Additionally, first and secondarticulated members are coupled at a pivot point to one another and tothe linear actuator. They further are pivotally coupled at distal endsthereof to respective ones of the first and second engagement arms,whereby the linear actuator urges the pivot point along a linear path toa latching position beyond where the first and second articulatedmembers are axially parallel. As previously noted, a resilient biasingarrangement that is installed on at least one of the first and secondengagement arms applies a resilient biasing force to the energy transfersystem. The resilient biasing arrangement applies a resilient biasingforce that maintains the engagement arrangement in the second position.

In accordance with a method aspect of the invention, there is provided amethod of testing a gear assembly of the type having an input and anoutput. The method includes the steps of:

installing the gear assembly on a mounting arrangement that resilientlypermits motion of the gear assembly in all directions, and that has aresilient frequency characteristic that excludes all natural frequenciesof the gear assembly;

applying a torque at the input of the gear assembly, whereby the gearassembly is rotatably operated;

applying a load at the output of the gear assembly; and

sensing a predetermined operating characteristic of the gear assembly.

In one embodiment of this method aspect of the invention, the step ofsensing is provided with the step of detecting acoustic energy issued bythe gear assembly. Also, the step of detecting acoustic energy issued bythe gear assembly is provided with the step of placing a microphone nthe vicinity of the gear assembly.

In a further embodiment, the step of sensing is provided with the stepof detecting vibratory displacement energy issued by the gear assembly.The step of detecting vibratory displacement energy issued by the gearassembly is provided with the further step of effecting communicationbetween an accelerometer and the gear assembly, and the step ofdetecting vibratory displacement energy issued by the gear assembly isprovided with the further step of effecting communication between avelocity sensor and the gear assembly.

After performing the step installing there is further provided the stepof clamping the gear assembly to the mounting arrangement. In anembodiment where the mounting arrangement is installed on a referencebase portion, the step of clamping is performed in response to thefurther step of applying a clamping actuation force to a clampingarrangement with respect to the reference base portion. A clampingactuation force is applied, and the gear arrangement is enabled to movefreely independent of the reference base portion.

In a further embodiment, the step of applying a clamping force isprovided with the further step of applying a resilient clamping force tothe gear assembly. This step may, in certain embodiments, include thefurther step of monitoring a predetermined dimension of the gearassembly in response to the step of clamping. This is accomplished byuse of a sensor that measures distance traveled.

Sensing is effected by monitoring a first sensor that receives acousticenergy that is responsive to a qualitative condition of the gearassembly in a drive mode of operation. When the drive mode of operationis in a first direction of operation, the qualitative condition of thegear assembly in the drive mode of operation includes a qualitativecondition of a first surface of the teeth of the gear assembly. Alsowhen drive mode of operation is in a first direction of operation, thequalitative condition of the gear assembly in the drive mode ofoperation includes a qualitative condition of a profile of a gear of thegear assembly, and a qualitative condition of the eccentricity of a gearof the gear assembly. Additionally, the qualitative condition of thegear assembly in the drive mode of operation includes a qualitativecondition of the angular orientation of the gears of the gear assembly.In still further embodiments of the method aspect of the invention,wherein the drive mode of operation is in a first direction ofoperation, the qualitative condition of the gear assembly in the drivemode of operation includes a qualitative condition of a plurality ofmoving components of the gear assembly.

In a further embodiment of the invention, the step of sensing isprovided with the further step of monitoring a second sensor thatreceives acoustic energy that is responsive to a qualitative conditionof the gear assembly in a coast mode of operation. The coast mode ofoperation includes a qualitative condition of a second surface of theteeth of the gear assembly. When the coast mode of operation is in afirst direction of operation, the qualitative condition of the gearassembly in the coast mode of operation includes a qualitative conditionof a profile of a gear of the gear assembly. Additionally, thequalitative condition of the gear assembly in the coast mode ofoperation includes a qualitative condition of the eccentricity of a gearof the gear assembly, as well as the angular orientation of the gears ofthe gear assembly. In further embodiments, the coast mode of operationincludes a qualitative condition of a plurality of moving components ofthe gear assembly.

In accordance with a further embodiment of this method aspect of theinvention, the drive and coast modes of operation are cyclical over aperiod that is shorter than a cycle period of the input of the gearassembly. Conversely, the period can be longer than a cycle period ofthe input of the gear assembly. This will depend, to an extent, upon theoperating ratios within the system under test. In situations where thesystem under test is an electrical system, harmonics and signaldistortions may affect the apparent cycle period in relation to thecycle period of the input energy.

In an advantageous embodiment, the first and second sensors are disposedat respective locations that are distal from each other, with the gearassembly interposed therebetween. This enables distinguishing betweenoperating modalities of the system under test, as well as facilitatinganalysis of operating characteristics of the system under test that havedirectional components.

In accordance with a clamping aspect of the present invention, there isprovided an arrangement for clamping a workpiece to a resilient supportelement. In this aspect of the invention, there is provided a supportbase installed on the resilient support element. First and secondclamping arms are each coupled to the support base by a respective firstpivot coupling and arranged to rotate pivotally about the respectivefirst pivot couplings between respective clamped and released counterrotational positions. Each of the first and second clamping arms isfurther provided with a respective second pivot coupling. First andsecond links are included in the combination, each having a respectivecentral axis between a respective first pivot coupling where the firstand second links are pivotally coupled to one another, and respectivesecond pivot couplings where each of the first and second links iscoupled to a second pivot coupling of a respectively associated one ofthe first and second clamping arms. A drive arrangement urges the firstand second links from a first angulated link position corresponding tothe released counter rotational position of the first and secondclamping arms to a second angulated link position on the other side of acoaxial position of the first and second links, the second angulatedlink position corresponding to the clamped counter rotational positionof the first and second clamping arms. Also, a drive coupler is arrangedto couple drive arrangement to at least one of the first and secondlinks whereby the drive arrangement is decoupled from the first andsecond links when the links are in the second angulated link position.

In one embodiment of the clamping aspect of the invention, the drivecoupler is coupled to the first pivot couplings of the first and secondlinks. In an embodiment where the workpiece has a vibratory displacementcharacteristic, the clamping arrangement is substantially freelydisplaceable in response to the vibratory displacement characteristic ofthe workpiece while the first and second links are in the secondangulated link position.

A sensor is installed on at least one of the first and second clampingarms for detecting a predetermined operating characteristic of theworkpiece. The may detect a displacement of the workpiece, or anacoustical energy issued by the workpiece.

In an embodiment where the workpiece is a gear assembly having arotatory input and an output, there is additionally provided a rotatorydrive for applying a torque at the rotatory input of the gear assembly.Also, a drive coupler couples the rotatory drive to the rotatory inputof the gear assembly. The drive coupler is arranged to providesubstantially exclusively torque to the gear assembly at its rotatoryinput, without any substantial axial loading, and to attenuate thepropagation of acoustic energy from the rotatory drive arrangement. Aload is coupled to the output of the gear assembly, the load beingarranged to simulate an actual operating condition of the gear assembly.

In accordance with a drive coupling aspect of the invention,substantially exclusively torque is transmitted from a drive arrangementto a gear assembly under test. The drive coupling arrangement includes afirst coupler portion attached to the drive coupling arrangement, thecoupler having a polygonal cross-sectional configuration that extendscontinuously over a predetermined length of axis. The polygonalcross-sectional configuration has a plurality of substantially planarsurfaces that extend parallel to the predetermined length of axis. Asecond coupler portion is provided and has an internal cross-sectionalconfiguration that accommodates the polygonal cross-sectionalconfiguration of said first coupler portion. The second coupler portionis provided with a plurality of engagement portions that communicateexclusively with a predetermined number of the substantially planarsurfaces of said first coupler portion. The first and second couplerportions are axially translatable along said first coupler portion for aportion of the predetermined length of axis. Therefore, the torque istransmitted between the first and second coupler portions withoutexerting an axial load.

In one embodiment of this drive coupling aspect of the invention, thepolygonal cross-sectional configuration corresponds to a hexagon. Also,the second coupler portion has three engagement portions that engagethree respective planar surfaces of the first coupler portion.

In accordance with a further method aspect of the invention, there isprovided a method of signal analysis for processing information from agear system under test. This further method aspect includes the stepsof:

driving the gear system under test by application of a rotatory input;

producing a first signal responsive to the torque applied to the gearsystem under test;

producing first digital data responsive to a first correlation betweenthe first signal and time;

measuring peaks in said first digital data to determine whether thepeaks exceeds a predetermined threshold magnitude; and

first subjecting those of the peaks that exceed the predeterminedthreshold magnitude to harmonic analysis.

In a specific illustrative embodiment of the invention of this furthermethod aspect, there is provided the further step of comparing theresult of the harmonic analysis of the step of first subjecting againstgear tooth harmonics to determine whether the peaks constitute ananomaly. Such an anomaly is a bump or a nick on a tooth of the gearsystem under test.

In a highly advantageous embodiment of the invention wherein improvedresults are obtained, there are provided the further steps of:

producing a second signal responsive to a noise produced by the gearsystem under test in response to the step of driving;

producing a second digital data responsive to a second correlationbetween the second signal and time;

identifying peaks in the second digital data that are simultaneous withpeaks in said first digital data;

measuring the simultaneous peaks in the second digital data to determinewhether they exceed a second predetermined threshold magnitude; and

second subjecting those of the simultaneous peaks in the second digitaldata that exceed the second predetermined threshold magnitude toharmonic analysis.

As is the case in the embodiment where only the torque signal issubjected to harmonic analysis, there is additionally provided in thisembodiment the further step of comparing the result of the harmonicanalysis of the steps of first subjecting and second subjecting againstgear tooth harmonics to determine whether the simultaneous peaksconstitute an anomaly. Thus, in this embodiment, the torque and thenoise signals are subjected to harmonic analysis. It is desired in anembodiment of the invention that is used to test gear systems, todetermine whether the anomaly is a bump or a nick on a tooth of the gearsystem under test. In a further step of calculating, the severity of theanomaly determined in the step of comparing is determined.

In a still further embodiment of this method aspect, there are providedthe further steps of:

establishing predetermined harmonic criteria; and

determining whether the results of the analysis in the step ofsubjecting conforms to the predetermined harmonic criterial of the stepof establishing.

In accordance with a still further method aspect of the invention, thereis provided a method of signal analysis for processing information froma gear system under test for determining the presence of bumps or nickstherein. In this still further method aspect, there are provided thesteps of:

driving the gear system under test by application of a rotatory input;

producing a first signal responsive to the torque applied the gearsystem under test;

producing a second signal responsive to a noise produced by the gearsystem under test in response to the step of driving;

producing first digital data responsive to a first correlation betweenthe first signal and time;

producing a second digital data responsive to a second correlationbetween the second signal and time;

identifying simultaneous peaks in the first and second digital data;

measuring the simultaneous peaks in the first and second digital data todetermine whether they exceed a predetermined threshold magnitude; and

subjecting those of the simultaneous peaks that exceed the predeterminedthreshold magnitude to harmonic analysis.

In one embodiment of this method aspect, there is provided the furtherstep of comparing the result of the harmonic analysis of the step ofsubjecting against gear tooth harmonics to determine whether thesimultaneous peaks constitute an anomaly. In a further embodiment, thereis provided the further step of calculating the severity of the anomalyof the step of comparing.

BRIEF DESCRIPTION OF THE DRAWING

Comprehension of the invention is facilitated by reading the followingdetailed description, in conjunction with the annexed drawing, in which:

FIG. 1 is a front plan representation of an arrangement for isolating asystem under test, constructed in accordance with the principles of theinvention;

FIG. 2 is a side plan view of the embodiment of FIG. 1;

FIG. 3 is an exploded plan representation of the embodiment of FIG. 1showing certain drive components;

FIG. 4 is a top plan view of the embodiment of FIG. 1;

FIG. 5 is a partially phantom front plan view of a drive arrangementthat supplied rotatory mechanical energy to an isolate mechanical energytransfer system under test;

FIG. 6 is side plan view of the drive system of FIG. 5;

FIG. 7 is a side plan representation of the drive system as shown inFIG. 6, enlarged to show greater detail;

FIG. 8 is a side plan view of a coupler that couples the drive system tothe mechanical system under test;

FIG. 9 is a top plan view of the coupler of FIG. 8 showing therein threeengagement surfaces for coupling with the flanks of an hexagonal nut(not shown in this figure) at the rotatory input of the mechanicalsystem under test;

FIG. 10 is a plan representation of a clamping arrangement constructedin accordance with the principles of the invention, the clampingarrangement being shown in two positions;

FIG. 11 is a compact drive arrangement constructed in accordance withthe invention for coupling the rotatory output of a mechanical energytransfer system under test to a rotatory load;

FIG. 12 is a partially cross-sectional side plan view of the compactdrive arrangement of FIG. 11 further showing a resilient couplingelement;

FIG. 13 is a partially phantom enlarged representation of the resilientcoupling element shown in FIG. 12;

FIG. 14 is an isometric representation of an arrangement for isolating asystem under test, constructed in accordance with the principles of theinvention, the system under test being an electrical energy transferdevice;

FIG. 15 is a process diagram of a typical process for conducting anenergy analysis;

FIG. 16 is a process diagram of a process for conducting an energyanalysis in accordance with the principles of the present invention; and

FIG. 17 is a process diagram of a process for conducting an energyanalysis in accordance with the principles of the present invention fordetermining bumps and nicks in a mechanical energy transfer system.

DETAILED DESCRIPTION

FIG. 1 is a front plan representation of an arrangement for isolating asystem under test, constructed in accordance with the principles of theinvention. As shown in this figure, an isolating arrangement 10 isarranged to support in relative isolation a mechanical drive system inthe form of a differential 11. Differential 11 is of the type that isconventionally employed in a motor vehicle (not shown) and is intendedto be tested for a variety of operating conditions, using isolatingarrangement 10. The differential is of the type having a rotatory input13 that receives rotatory mechanical energy from a drive arrangement(not shown in this figure) that will be described below. In addition,differential 11 has rotatory outputs 14 and 15, respectively, thatproduce rotatory mechanical energy in response to the rotatory inputenergy received at rotatory input 13. When employed in a motor vehicle(not shown), differential 11 is coupled to the drive shaft (not shown)of the vehicle at rotatory input 13, and rotatory outputs 14 and 15 arecoupled to the vehicle's drive wheels (not shown).

Differential 11 is shown to be supported on a pair of supports 18 and 19that are installed on a base 20. Each of supports 18 and 19 hasinstalled thereon a respectively associated one of resilient isolatingelements 22 and 23. A respective one of engagement arrangements 24 and25 are installed on resilient isolating elements 22 and 23. Theengagement arrangements will be described in detail hereinbelow andserve to couple differential 1 1 at its rotatory outputs 14 and 15whereby it is secured with respect to base 20, yet limited motion ofdifferential 11 is permitted relative to base 20.

FIG. 1 further shows a pair of load arrangements 28 and 29 that apply acontrollable load to respectively associated ones of rotatory outputs 14and 15. The rotatory outputs are coupled mechanically (coupling notshown in this figure) to load arrangements 28 and 29 in a manner thatfacilitates limited motion of the rotatory outputs with respect to base20. The permissible displacement of differential 11 in accordance withthe present invention is along multiple planes of freedom, and, as willbe described hereinbelow, the coupling arrangements (not shown in thisfigure, between rotatory outputs 14 and 15 and their respectiveassociated load arrangements 28 and 29 permit axial and rotative degreesof freedom of motion. Such couplings will be described with respect toFIGS. 9-12.

FIG. 2 is a side plan view of the embodiment of FIG. 1. This figure istaken along line 2—2 of FIG. 1. In addition to some of the structureshown in FIG. 1, FIG. 2 shows a safety cover 30 that protects the user(not shown) of the isolating arrangement in accordance with establishedsafety standards. Elements of structure that correspond to thosediscussed hereinabove with respect to FIG. 1 are similarly designated.

FIG. 2 shows engagement arrangement 24 having engagement arms 32 and 33that are shown in an engaged position around rotatory output 14. As willbe described hereinbelow, engagement arms 32 and 33 have engaged anddisengaged (not shown) positions in response to actuation of anengagement driver which is shown in. this figure in the form of a linearactuator 35.

A safety cover 30 is shown to be coupled to a cover hinge 31, wherebythe safety cover is rotatable thereabout in response to actuation of acover actuator 34. In operation, the safety cover is arranged in theposition shown in the figure during performance of the testingprocedure, and it is raised to a position that is not shown in order tofacilitate installation and removal of the system under test, i.e.,differential 11.

FIG. 2 additionally shows a drive motor 40, which in this embodiment, iscoupled to a belt pulley 42, shown in FIG. 1.

FIG. 3 is an exploded plan representation of the embodiment of FIG. 1showing certain drive components. Elements of structure that havepreviously been discussed are similarly designated. The drivearrangement, and the manner by which it is coupled to differential 11,will be discussed in detail hereinbelow with respect to FIGS. 5-8.

FIG. 4 is a top plan view of the embodiment of FIG. 1. Elements ofstructure that have previously been discussed are similarly designated.Moreover, differential 11 has been removed, and therefore, is notvisible in this figure.

In FIG. 4, each of load arrangements 28 and 29 has associated therewitha respective one of load coupler arrangements 44 and 45, each of whichis coupled by a respective load belt 46 and 47 to a respective one ofload units 48 and 49. Load arrangement 28 will be described in detailhereinbelow with respect to FIG. 11, and the load coupler arrangements,44 and 45, will be described in detail with respect to FIG. 12.Referring to FIG. 4, rotatory outputs 14 and 15 (not shown in thisfigure) are coupled (coupling not shown in this figure) to respectivelyassociated ones of load coupler arrangements 44 and 45 which, aspreviously noted, provide multiple degrees of freedom of movement. Loadunits 48 and 49, in this specific illustrative embodiment of theinvention, are in the form of electric brakes or electric motors. Ofcourse, other forms of loads can be employed in the practice of theinvention. In embodiments of the invention where the load units are inthe form of electric motors, such motors can provide simulated brakingand driving operations. Thus, in the present embodiment where theisolating arrangement is directed to the testing of a drive componentfor a vehicle, such as a differential, the. load units can be operatedin a drag, or generator mode, wherein the differential would be operatedin a simulated drive mode. That is, the load is driven by thedifferential. Alternatively, the load units can be operated in a motordrive mode, wherein the differential is itself driven by the load, i.e.,operated in a simulated coast mode. In a highly advantageous embodimentof the invention, the differential can be operated and thereby tested indrive and coast modes of operation in forward and reverse directions. Itis to be remembered that during drive and coast modes of operationdifferent gear tooth surfaces (not shown) within the differential arecaused to communicate with one another, thereby affording enhancedtesting capability.

FIG. 5 is a partially phantom front plan view of a drive arrangementthat supplies rotatory mechanical energy to an isolated mechanicalenergy transfer system under test. Elements of structure that havepreviously been discussed are similarly designated. As shown in thisfigure, output shafts 52 and 53 are shown protruding from the fragmentedrepresentation of rotatory outputs 14 and 15, respectively. The outputshafts rotate in response to the application of a rotatory drive atrotatory input 13.

FIG. 6 is side plan view of the drive system of FIG. 5. The operation ofthe drive arrangement that will supply a rotatory drive to rotatoryinput 13 of differential 11 is described herein with reference to FIGS.5-9. As stated, drive motor 40 is coupled via a drive belt 41 to beltpulley 42 which is installed on a drive shaft 55 that is shown in thefigures to extend axially vertically. Belt pulley 42 contains a torquesensing arrangement (not shown) that provides an electrical signalresponsive to torque differential between the belt pulley and driveshaft 55. The electrical signal responsive to torque (not shown) isavailable at signal output connector 56.

In this specific illustrative embodiment of the invention, the torquesensing arrangement contained within belt pulley 42 and its associatedsignal output connector 56 is in the form of a strain gauge (not shown)installed to respond to the displacement of a web (not shown). That is,in the practice of this aspect of the invention, torque is transmittedacross a web whereby, for example the torque is applied across theperiphery of the web, and an output shaft is coupled nearer to thecenter of the web. Of course, these may be reversed. As torque isapplied, the web is correspondingly deformed, and a strain gaugeinstalled on the web measures the deformity in the web in response tothe applied torque. Over a predetermined range of torque, thedeformation of the web, as determined by the strain gauge, can becorrelated to the magnitude of the applied torque. Signal outputconnector 56, in this specific illustrative embodiment of the invention,additionally contains circuitry (not shown) that is AC coupled to thetorque sensing arrangement, and that modulates and demodulates theresulting torque signal.

Shaft 55 is shown in FIG. 6 to be supported against axially transversemotion by a pair of journal bearings 58. Drive shaft 55, therefore,rotates about its axis in response to a rotatory drive energy suppliedby drive motor 40 and delivered thereto by drive belt 41.

A coupling arrangement 60 that is fixed axially onto drive shaft 55permits resilient axial displacement of a coupling shaft 62 with respectto the axis of drive shaft 55. Coupling arrangement 60 is formed of aflanged member 61 that is coupled to rotate with drive shaft 55. Afurther flanged member 63 is shown to be engaged with coupling shaft 62.Flanged members 61 and 63 are each provided with respective resilientelements 65 that facilitate the permissible axial displacement ofcoupling shaft 62 with respect to the central axis defined by driveshaft 55. The rotatory energy is transmitted across intermediate element67, with which resilient elements 65 communicate.

FIG. 7 is a side plan representation of the drive system as shown inFIG. 6, enlarged to show greater detail. As shown in FIGS. 6 and 7, theuppermost end of coupling shaft 62 is arranged to be connected torotatory input 13 of differential 11 (shown in fragmented form in thesefigures). Differential 11 is of the conventional type having anhexagonal nut 69 (FIG. 7) installed at rotatory input 13. Rotatory input13 is formed as a pinion shaft, and hexagonal nut 13 is threadedlyengaged therewith. The application of a high tightening torque tohexagonal nut 13 during assembly of the differential prevents same fromloosening during application of the rotatory energy via coupling shaft62.

FIG. 7 shows differential 11 in the process of being installed ontocoupling shaft 62, and therefore hexagonal nut 69 is shown in twopositions, where it is designated 69 and 69′, respectively. Uponcompletion of the installation of differential 11, hexagonal nut 69becomes engaged with a nut driver 70. Nut driver 70 is axiallytranslatable, and therefore is shown in two positions, where it isdesignated 70 and 70′.

FIG. 8 is a side plan view of nut driver 70 that couples the drivesystem to the mechanical system under test. FIG. 9 is a top plan view ofnut driver 70 of FIG. 8 showing therein three engagement surfaces forcoupling with the flanks of an hexagonal nut (not shown in this figure)at the rotatory input of the mechanical system under test. As shown inFIG. 8 and FIG. 9, nut driver 70 has a tapered outward appearance whenviewed from the side (FIG. 8). Internally, nut driver 70 is providedwith three engagement surfaces 71. The engagement surfaces engage withthe flank surfaces of the nut (not shown) at rotatory input 13 ofdifferential 11. The nut driver is, as previously noted, axiallydisplaceable along the axis of coupling shaft 62, and is urged upwardtoward the nut at the rotatory input of the differential by operation ofa resilient spring member 72 (FIG. 6). Thus, the nut driver is urgedinto communication with the nut by operation of the light resilient biassupplied by spring 72, thereby ensuring engagement between nut driver 70and the hexagonal nut (not shown in FIGS. 8 and 9) at the rotatory inputof differential 11. It is to be noted that the light axial bias appliedby the engagement spring is negligible and affords the differential adegree of freedom of movement in the axial direction.

Referring once again to FIG. 7, sensors 73-76 are shown for monitoringvarious aspects of the operation of the differential in response to theapplication of the rotatory input. For example, in one embodiment of theinvention, the various sensors are configured to monitor angularposition of the rotatory input, transaxial displacement of the driveshaft, transaxial displacement of the differential in response to theapplication of the rotatory input energy, temperature in the region ofthe input bearing (not shown) of the differential, acoustic noise, etc.

FIG. 10 is a plan representation of a clamping arrangement constructedin accordance with the principles of the invention, the clampingarrangement being shown in two positions. Elements of structure thatcorrespond to those previously described are similarly designated. Asshown, support 18 is coupled to base 20, illustratively via one or morefasteners 140. In this embodiment, a pair of resilient support elements141 are disposed on support element 18 and there is supported thereon anisolation support 142. The isolation support has a central V-shapedregion 144 in the vicinity of which are installed support bearings 146and 147. Rotatory output 14 of differential 11 (not shown in thisfigure) rests on the support bearings.

Engagement arms 32 and 33, as previously noted, have first and secondpositions corresponding to open and closed conditions. Engagement arms32 and 33 are shown in the closed condition, wherein rotatory output 14is clamped to support bearings 146 and 147. When the support arms are inthe open position, identified as 32′ and 33′ (shown in phantom), thedifferential can be removed or installed onto isolation support 142.Actuation of the engagement arms between the open and closed conditionsis effected by operation of linear actuator 35 which is coupled to theengagement arms by respectively associated ones of engagement couplerlinks 148 and 149. Engagement coupler links 148 and 149 are each coupledat a respective first ends thereof to a respectively associated one ofengagement arms 32 and 33, and they each are coupled to one another at acentral pivot coupling 150. An armature 151 of linear actuator 35travels vertically to effect clamping and release of rotatory output 14.

When armature 151 is extended upward, engagement arms 32 and 33 areurged toward rotatory output 14, whereby spring-loaded contacts 152 and153 communicate with rotatory output 14. In this embodiment, thespring-loaded contacts exert a resilient biased force against rotatoryoutput 14 facilitating the latching of the engagement arms by operationof armature 151. As shown, when the armature is extended fully upward,engagement coupler links 148 and 149 are urged beyond the point wheretheir respective axes are parallel, and therefore, the engagementcoupler links are biased against the underside of isolation support 142.It should be noted that the pivot pin (not specifically shown) coupledto armature 151 at pivot coupling 150 has a smaller diameter than theapertures in the engagement coupler links. Thus, during testing of thevibration and noise of the differential, armature 151 of linear actuator35 is essentially decoupled from engagement coupler links 148 and 149and isolation support 142.

When it is desired to remove differential 11 from isolating arrangement10, armature 151 is withdrawn, whereupon pivot coupling 150 istranslated to the location identified as 150′. In this position, theengagement arms are translated to the location shown in phantom as 32′and 33′.

In a further embodiment of the invention, one or both of spring-loadedcontacts 152 and 153 is provided with a displacements sensor 154 thatproduces an electrical signal, or other indication, responsive to theextent of inward translation of the spring-loaded contact. Such anindication would be responsive to the outside dimension of the rotatoryoutput of differential 11, thereby providing a means for determiningdimensional variations of the differential housing (not specificallyidentified in this figure) during a production run.

FIG. 11 is a compact drive arrangement constructed in accordance withthe invention for coupling the rotatory output of a mechanical energytransfer system under test (not shown in this figure) to a rotatoryload, which will be described hereinbelow in the form of an electricrotatory device that is operable in drive and generator modes. As shownin this figure, a load arrangement 80 is provided with a load motor 81having a belt pulley 82 arranged to rotate with a load motor shaft 83.

In this specific embodiment, pulley 82 is coupled to a further beltpulley 85 via a load belt 86. Pulley 85 is coupled to a tubular shaft 89having a flanged portion 90 that is arranged in axial communication withtubular shaft 89. In a manner similar to that of pulley 46 in FIG. 6,belt pulley 82 in FIG. 11 contains a torque sensing arrangement 87 thatprovides an electrical signal (not shown) responsive to a torquedifferential between the belt pulley and load motor shaft 83. Theelectrical signal responsive to torque is available at signal outputconnector 84, as described below.

In this specific illustrative embodiment of the invention, torquesensing arrangement 87 contained within belt pulley 82 and itsassociated signal output connector 84 include a strain gauge 88installed to respond to the displacement of a web 92. That is, in thepractice of this aspect of the invention, torque is transmitted acrossweb 92 wherein, for example, the torque is applied across the peripheryof the web, and an output shaft 98 is coupled nearer to the center ofthe web. Of course, the application of the torque may be rotationallyreversed. As the torque is applied, web 92 is correspondingly deformed,and strain gauge 88 installed on the web measures the deformity in theweb in response to the applied torque. Over a predetermined range oftorque, the deformation of web 92, as determined by measurement of theelectrical response of strain gauge 88 at signal output connector 84,can be correlated to the magnitude of the applied torque.

As described hereinabove with respect to signal output connector 56 inFIG. 6, in this specific illustrative embodiment of the invention,signal output connector 84 in FIG. 11 additionally contains circuitry(not shown) that is AC coupled to the torque sensing arrangement, andthat modulates and demodulates the resulting torque signal. The torquesignal will be to a significant extent responsive to the load or drivecharacteristic of load motor 81, which is controllable by theapplication of appropriate electrical signals (not shown) or connectionof electrical loads (not shown) at electrical terminals 99 thereof.

Tubular shaft 89 is supported rotatably by ball bearings 91. On theother side of pulley 85 is arranged a resilient element 93 that issecured to remain in communication with pulley 85 by operation of an endcap 94. End cap 94 has internally affixed thereto a load shaft 95 thatis arranged to extend along the interior length of tubular shaft 89.Thus, notwithstanding that tubular shaft 89 is axially fixed in asupport 96, load shaft 95 will rotate with the tubular shaft but canexperience displacement transverse to axis of rotation 98. Thus, anyrotatory element (not shown in this figure) that would be coupled toload shaft 95 at its associated coupler 97 would be provided withfreedom of motion in any direction transverse to the axis of rotation ofthe load shaft, and therefore would not be constrained in the axiallytransverse direction.

FIG. 12 is a partially cross-sectional side plan view of a compact drivearrangement similar in some respects to that of FIG. 11. This figureshows a shaft support system 100 that provides the degree of freedom ofmotion discussed hereinabove with respect to the embodiment of FIG. 11,and additionally provides axial thrust support. Shaft support system 100is provided with a pulley 101 that can be coupled to another rotatoryelement (not shown) via a belt 102. The pulley is fixed to a tubularshaft 104 that is axially fixed in a support 105 by ball bearings 106.At the other end of tubular shaft 104, the tubular shaft is expandedradially to form a shaft portion 108 having a large diameter than thecentral portion of the tubular shaft. A resilient coupling arrangementthat is generally designated as 1 10 is resiliently coupled to shaftportion 108. Resilient coupling arrangement 110 is provided with anintermediate plate 111 and an end plate 112 that are resiliently coupledto one another whereby they rotate with tubular shaft 104. A centralshaft 114 is coupled at its right-most end to end plate 112 so as to berotatable therewith. The central shaft, however, experiences freedom ofmovement in all directions transverse to its axis of rotation. Anytravel of central shaft 114 toward the right hand side is limited by anend stop 115, which is arranged, in this embodiment, to provide ameasure of axial adjustment. The other end of central shaft 114 iscoupled to a resilient coupling arrangement which is generallydesignated as 117.

FIG. 13 is a partially phantom enlarged representation of the resilientcoupling element shown in FIG. 12. Resilient coupling element 117 isshown in this figure in an expanded form to facilitate this detaileddescription. Central shaft 114 (FIG. 12) has a reduced diameter endportion 120 on which is installed a flanged washer 121 having a reduceddiameter portion 122 and a flange 123 formed therearound. A furtherflanged element 125 is installed on reduced diameter end portion 120 ofcentral shaft 114, a shear pin 127 being disposed between flanged washer121 and further flanged element 125. In addition, an annular portion 128is arranged to surround the flanged washer and the further flangedelement, and to overlie circumferentially the axial region whereresilient element 127 is disposed. All of these elements are secured toreduced diameter end portion 120 of central shaft 114 by a fastener 129and a washer 130. As shown, fastener 129 is threadedly engaged axiallyonto the end of central shaft 114.

A support portion 132 is fixed onto further flanged element 125 byfasteners 133. Support portion 132 is resiliently coupled to a flangedshaft 135 by means of studs 136. Thus, even though central shaft 114enjoys freedom of movement transverse to its axis of rotation, resilientcoupling arrangement 117 provides yet further freedom of movement in alldirections transverse to the axis of rotation for flanged shaft 135.Flanged shaft 135, in one embodiment of the invention, is ultimatelycoupled to a rotatory output, such as rotatory output 15 of FIG. 1.Alternatively, shaft support system 100 can be used in the drivearrangement of FIG. 6 to provide significant degree of motion lateral tothe axis of rotation to the drive shaft.

FIG. 14 is an isometric representation of an arrangement for isolating asystem under test, the isolation system being constructed in accordancewith the principles of the invention. In this embodiment, the systemunder test is an electrical energy transfer device. As shown in thisfigure, an isolation support 160 isolates an electrical energy transferdevice, illustratively in the form of an electrical transformer 162. Theelectrical transformer is secured to an isolation base 164 by operationof a toggle locking device 165. Isolation base 164 is mechanicallyisolated from a ground surface 166 by a plurality of resilient isolationelements 170. That is, the isolation base is permitted freedom ofmovement in at least one plane of motion, and preferably a plurality ofplanes of motion, by operation of the resilient isolation elements.

In the practice of this specific illustrative embodiment of theinvention, the resilient isolation elements have a resiliencecharacteristic that, as previously noted in regard of other embodimentsof the invention, exclude a natural frequency of isolation support 160and transformer 162. The motion of the transformer and the isolationsupport is therefore responsive substantially entirely to the electricalenergy that is transferred to or from transformer 162 via its electricalterminals 172.

FIG. 15 is a process diagram of a typical process for conducting anenergy analysis of a gear system. In this known system, gears under test180 are driven by a drive 181, the speed of which is controlled by aspeed control 183. Information relating to the drive speed is conductedto a digital data storage system 185.

Analog sensors 187 obtain analog data from gears under test 180, theanalog signals from the sensors being conducted to an A/D converter 188.The A/D converter performs the conversion of the analog signals inresponse to a clock 190, and the resulting digital data is conducted todigital data storage system 185. Thus, digital data storage system 185contains the digitized analog signals obtained from sensors 187, whichdata is correlated to the speed at which gears under test 180 aredriven.

The digital data of digital data storage system 185 is converted to thefrequency domain by subjecting same to a fast Fourier transform at step193. The resulting frequency components are then ordered at step 194 andanalyzed manually at step 195. At this step, the collected data, in thefrequency domain, is analyzed in the context of predetermined testcriteria. The pass/fail decision is then made at step 197, and if thepredetermined criteria is not met, a “fail” indication is produced atstep 198. Otherwise, a “pass” indication is issued at step 199.

FIG. 16 is a process diagram of a process for conducting an energyanalysis in accordance with the principles of the present invention. Asshow in this figure, gears under test 201 are driven into rotation by adrive system 202, which also drives an encoder 204. Encoder 204 deliverssignals responsive to the rotation of gears under test 201 to an A/Dconverter 206. In this embodiment, the signal from encoder 204 serves asa pacing clock for the A/D converter. Information relating to noise anddisplacement issued by the gears under test is collected by analogsensors 207. The resulting analog signals are conducted to A/D converter206 where they are converted to digital signals correlated to therotation of drive system 202.

The digital signals from A/D converter 206 are conducted to a digitaldata store 210 where they are maintained in correlation to the driveinformation obtained from encoder 204. In this specific illustrativeembodiment of the invention, the digital data is storedtwo-dimensionally, wherein sensor signal amplitude is identified withthe y-axis, and rotational position is identified with the x-axis. Thecorrelated digital data is subjected to a fast Fourier transform at step212 wherein the data is converted into its frequency components.

Data in the frequency domain is subjected to processing at step 214,where a power spectrum density is created using a data window. The powerspectrum density data is then analyzed harmonically at step 215 todetermine its relationship with predetermined test criteria. Thedecision whether the power spectrum density data passes or fails withrespect to predetermined test criteria is made at step 216, and thepredetermined criteria is not met, a “fail” indication is produced atstep 217. Otherwise, a “pass” indication is issued at step 218.

FIG. 17 is a diagram of a process for conducting an analysis 230 inaccordance with the principles of the present invention for determiningbumps and nicks in a mechanical energy transfer system. As show in thisfigure, gears under test 231 are driven into rotation by a drive system232, via a torque sensor 234. Torque sensor 234 delivers signalsresponsive to the rotatory force supplied to gears under test 231 to anA/D converter 236. Information relating to noise and displacement issuedby the gears under test is collected by noise sensors 237, which mayinclude velocity sensors (not shown in this figure), accelerometers (notshown in this figure), microphones (not shown in this figure), etc. Theresulting noise signals are conducted to A/D converter 236 where theyare converted to digital signals correlated to the torque applied bydrive system 232 to gears under test 231.

The digital signals from A/D converter 236 are conducted to a digitaldata store 240 where they are maintained in correlation to the driveinformation obtained from torque sensor 234. In this specificillustrative embodiment of the invention, the digital data is stored astwo two-dimensional data sets, wherein noise sensor signal amplitude isidentified with a first y-axis, and time is identified with the x-axis.The amplitude of the torque signal is identified with a second y-axis,and time is again identified with the x-axis.

Correlated data from digital data store 240 is subjected to analysis atstep 242, wherein peaks that occur simultaneously in the torque andnoise signal waveforms are identified. These peaks are then measured atstep 244 to determine whether they exceed predetermined thresholds.Those peaks that exceed the predetermined thresholds are then tested atstep 245 against the harmonics of each gear tooth frequency, todetermine whether the peaks correspond to anomalous conditions.

The decision whether the gears under test pass or fail with respect topredetermined test criteria is made at step 246, and if thepredetermined criteria is not met, a “fail” indication is produced atstep 247. Otherwise, a “pass” indication is issued at step 248. In someembodiments of the invention, a calculation of the severity of the bumpsor nicks that caused the anomalous conditions is calculated at step 249.

In one embodiment of the process of FIG. 17, analysis is performed usingonly the torque data derived from torque sensor 234, without correlationto the noise data obtained from noise sensor 237. In this embodiment,therefore, noise sensor 237 need not be provided, as the noise signaltherefrom is not used. Thus, torque sensor 234 delivers signalsresponsive to the rotatory force supplied to gears under test 231 to A/Dconverter 236, and the digital data is stored as a singletwo-dimensional data set, wherein the amplitude of the torque signal isidentified with the y-axis, and time is identified with the x-axis.

Peaks in the torque signal are then measured at step 244 to determinewhether they exceed a predetermined threshold. Those peaks that exceedthe predetermined thresholds are then tested at step 245 against theharmonics of each gear tooth frequency, to determine whether the peakscorrespond to anomalous conditions.

The decision whether the gears under test pass or fail with respect topredetermined test criteria is made at step 246, and if thepredetermined criteria is not met, a “fail” indication is produced atstep 247. Otherwise, a “pass” indication is issued at step 248. Aspreviously noted, a calculation of the severity of the bumps or nicksthat caused the anomalous condition is calculated at step 249.

Although the invention has been described in terms of specificembodiments and applications, persons skilled in the art can, in lightof this teaching, generate additional embodiments without exceeding thescope or departing from the spirit of the claimed invention.Accordingly, it is to be understood that the drawing and description inthis disclosure are proffered to facilitate comprehension of theinvention, and should not be construed to limit the scope thereof

What is claimed is:
 1. An arrangement for isolating an energy transfersystem while it is subjected to a test process for noise, the energytransfer system being of the type having an energy input and at leastone energy output, the arrangement comprising: a base; an energy supplycoupled to the energy transfer system for supplying energy thereto; anisolation support for supporting the energy transfer system whereby theenergy transfer system is translatable in at least one plane of freedomwith respect to said base during receipt of, and in response to, theenergy supplied thereto by said energy supply; and an engagementarrangement for securing the energy transfer system to said isolationsupport, said engagement arrangement having a first position withrespect to said base wherein the energy transfer system is installableon, and removable from, said isolation support, and a second positionwherein the energy transfer system is secured to said isolation support.2. The arrangement of claim 1, wherein said energy supply is coupled tothe energy transfer system for supplying energy thereto when saidengagement arrangement is in said second position.
 3. The arrangement ofclaim 2, wherein the energy transfer system is a mechanical energytransfer system, and said energy supply comprises a source of rotatorymechanical energy.
 4. The arrangement of claim 3, wherein there isfurther provided a rotatory coupler for coupling said source of rotatorymechanical energy to the energy transfer system.
 5. The arrangement ofclaim 4, wherein said mechanical energy transfer system has forward andreverse directions of operation, and drive and coast modes of operationfor each of the forward and reverse directions of operation.
 6. Thearrangement of claim 5, wherein there the mechanical energy transfersystem contains at least a pair of meshed elements, at least one of saidpair of meshed elements being a gear having a plurality of gear teeththereon, said gear teeth each having first and second gear toothsurfaces for communicating with the other element of said pair of meshedelements, a mechanical energy transfer communication between the pair ofmeshed elements being effected primarily via the respective first geartooth surfaces during forward-drive and reverse-coast modes ofoperation, and primarily via the respective second gear tooth surfacesduring forward-coast and reverse-drive modes of operation.
 7. Thearrangement of claim 6, wherein there is further provided a firstacoustic sensor arranged at a first location in the vicinity of themechanical energy transfer system for producing a first signalresponsive substantially to a qualitative condition of said first geartooth surfaces.
 8. The arrangement of claim 7, wherein there is furtherprovided a second acoustic sensor arranged at a second location in thevicinity of the mechanical energy transfer system for producing a secondsignal responsive substantially to a qualitative condition of saidsecond gear tooth surfaces.
 9. The arrangement of claim 8, wherein thefirst and second locations are distal from each other on opposite sidesof said pair of meshed elements.
 10. The arrangement of claim 4, whereinsaid rotatory coupler comprises a resilient coupler arrangement thattransmits rotatory motion thereacross over a predetermined range ofrotatory motion transmission angles.
 11. The arrangement of claim 10,wherein said resilient coupler arrangement comprises first and secondcoupler portions, said first and second coupler portions being rigidlycoupled rotationally to each other, and axially resiliently coupled toeach other, whereby said first and second coupler portions aresynchronously rotatable over the predetermined range of rotatory motiontransmission angles.
 12. The arrangement of claim 10, wherein saidresilient coupler arrangement comprises first and second couplerportions, said first and second coupler portions being rigidly coupledrotationally to each other, and radially resiliently coupled to eachother, whereby said first and second coupler portions are synchronouslyrotatable over a predetermined range of axial displacement.
 13. Thearrangement of claim 3, wherein there is further provided a torquesensor interposed between said source of rotatory mechanical energy andthe energy transfer system for producing a signal responsive to a torqueapplied by said source of rotatory mechanical energy to the energytransfer system.
 14. The arrangement of claim 13, wherein said torquesensor comprises a torque-transmitting element having a predetermineddeformation characteristic, said torque-transmitting element beingdeformed in response to the torque applied by said source of rotatorymechanical energy to the energy transfer system.
 15. The arrangement ofclaim 14, wherein said torque sensor further comprises a strain sensorcoupled to said torque-transmitting element for producing a strainsignal responsive to the predetermined deformation characteristic ofsaid torque-transmitting element.
 16. The arrangement of claim 13,wherein said torque sensor is arranged to produce a static torque signalresponsive to the magnitude of torque required to initiate rotatorymotion in said mechanical energy transfer system.
 17. The arrangement ofclaim 13, wherein said torque sensor is arranged to produce a dynamictorque signal responsive to the magnitude of torque required to maintainrotatory motion in said mechanical energy transfer system.
 18. Thearrangement of claim 2, wherein the energy transfer system is anelectrical energy transfer system, and said energy supply comprises asource of electrical energy.
 19. The arrangement of claim 18, whereinthere is further provided an electrical load for receiving an outputelectrical energy from the energy transfer system when said engagementarrangement is in said second position.
 20. The arrangement of claim 2,wherein there is further provided a first sensor arranged to communicatewith the energy transfer system for producing an information signalresponsive to an operating characteristic of the energy transfer systemin response to the energy supplied by said energy supply.
 21. Thearrangement of claim 20, wherein said first sensor is arranged tocontact the energy transfer system for producing a signal responsive toa predetermined operating characteristic of the energy transfer systemin response to the energy supplied by said energy supply.
 22. Thearrangement of claim 20, wherein said first sensor is arranged tocontact said isolation support for producing a signal responsive to apredetermined operating characteristic of the energy transfer system inresponse to the energy supplied by said energy supply.
 23. Thearrangement of claim 20, wherein said first sensor is arranged to betranslatable relative to the energy transfer system.
 24. The arrangementof claim 20, wherein said first sensor comprises a microphone forproducing a signal responsive to an acoustic energy issued by the energytransfer system in response to the energy supplied by said energysupply.
 25. The arrangement of claim 24, wherein there is furtherprovided a signal controller for controlling the amplitude of the signalresponsive to the acoustic energy issued by the energy transfer systemin response to the energy supplied by said energy supply, said signalcontroller being responsive to a temperature characteristic of theenergy transfer system.
 26. The arrangement of claim 25, wherein saidsignal controller is nonlinearly responsive to the temperaturecharacteristic of the energy transfer system.
 27. The arrangement ofclaim 20, wherein said first sensor comprises a laser sensor forproducing a signal responsive to a displacement of the energy transfersystem in response to the energy supplied by said energy supply.
 28. Thearrangement of claim 20, wherein said first sensor comprises anaccelerometer.
 29. The arrangement of claim 20, wherein said sensorcomprises a velocity sensor.
 30. The arrangement of claim 1, whereinsaid isolation support comprises a resilient support element forsupporting the energy transfer system, said resilient support elementhaving a resilience frequency characteristic that excludes a naturalfrequency of any combination of said base, said engagement arrangement,and the energy transfer system.
 31. The arrangement of claim 1, whereinsaid isolation support supports the energy transfer system whereby it istranslatable in at least a second plane of freedom with respect to saidbase.
 32. The arrangement of claim 1, wherein there is further providedan engagement driver having a first portion for coupling to said base,and a second end for coupling to said engagement arrangement.
 33. Thearrangement of claim 32, wherein said engagement driver comprises alinear actuator having a first end for coupling to said base, and asecond end for coupling to said engagement arrangement, said linearactuator being arranged to drive said engagement arrangement betweensaid first and second positions, and being decoupled from saidengagement arrangement when said engagement arrangement is in the secondposition.
 34. The arrangement of claim 32, wherein there is furtherprovided an engagement coupler interposed between said engagementarrangement and said engagement driver means, said engagement couplercomprising: a support portion installed on said isolation support; firstand second engagement arms pivotally coupled to said support portion andfirst and second articulated members coupled at a pivot point to oneanother and to said engagement driver means, and being pivotally coupledat distal ends thereof to respective ones of said first and secondengagement arms, whereby said engagement driver means urges the pivotpoint along a predetermined path to a latching position beyond wheresaid first and second articulated members are axially parallel.
 35. Thearrangement of claim 34, wherein there is further provided resilientbiasing means installed on at least one of said first and secondengagement arms for applying a resilient biasing force to the energytransfer system.
 36. The arrangement of claim 35, wherein said resilientbiasing means applies a resilient biasing force that maintains saidengagement arrangement in the second position.
 37. The arrangement ofclaim 34, wherein there is further provided displacement sensor meansinstalled on at least one of said first and second engagement arms forproducing a distance signal responsive to a distance between the atleast one of said first and second engagement arms and the energytransfer system, the distance signal being responsive to a predetermineddimension of the energy transfer system.
 38. The arrangement of claim 1,wherein there is further provided a thermal sensor for producing athermal signal responsive to a temperature of the energy transfersystem.
 39. The arrangement of claim 38, wherein said thermal sensorcomprises an infrared sensor for communicating optically with the energytransfer system.
 40. The arrangement of claim 38, wherein said thermalsensor has a directional characteristic and is directed to apredetermined region of the energy transfer system for determining arate of change of temperature of the predetermined region with respectto time.
 41. The arrangement of claim 38, wherein the response of thevariation of the amplitude of the noise signal with respect totemperature is in accordance with a non-linear amplitude-temperaturerelationship.
 42. An arrangement for isolating a mechanical drive systemfor a vehicle while it is subjected to a testing process, the drivesystem being of the type having a rotatory input and at least onerotatory output, the arrangement comprising: a base; an isolationsupport for supporting the mechanical drive system whereby themechanical drive system is translatable in at least one plane of freedomwith respect to said base; an engagement arrangement for securing themechanical drive system to said isolation support, said engagementarrangement having a first position with respect to said base whereinthe mechanical drive system is installable on, and removable from, saidisolation support, and a second position wherein the mechanical drivesystem is secured to said isolation support; an engagement drivercoupled to said base and to said engagement arrangement for urging saidengagement arrangement between said first and second positions, saidengagement arrangement being coupled to said engagement driver when saidengagement arrangement is in said first position, and isolated from saidengagement driver when said engagement arrangement is in said secondposition; a rotatory drive for applying a rotatory drive force to themechanical drive system; and a drive coupler for transmitting a torquefrom said rotatory drive to the rotatory input of the mechanical drivesystem, whereby the mechanical drive system is translatable in the planeof freedom in response to the rotatory drive force.
 43. The arrangementof claim 42, wherein there is further provided a torque sensorinterposed between said rotatory drive and the mechanical drive systemfor producing a signal responsive to a torque applied by said rotatorydrive to the mechanical drive system.
 44. The arrangement of claim 43,wherein said torque sensor is arranged to produce a static torque signalresponsive to the magnitude of torque required to initiate rotatorymotion in said mechanical drive system.
 45. The arrangement of claim 43,wherein said torque sensor is arranged to produce a dynamic torquesignal responsive to the magnitude of torque required to maintainrotatory motion in said mechanical drive system.
 46. The arrangement ofclaim 43, wherein said torque sensor comprises a torque-transmittingelement having a predetermined deformation characteristic, saidtorque-transmitting element being deformed in response to the torqueapplied by said rotatory drive system to the mechanical drive system.47. The arrangement of claim 46, wherein said torque sensor furthercomprises a strain sensor coupled to said torque-transmitting elementfor producing a strain signal responsive to the predetermineddeformation characteristic of said torque-transmitting element.
 48. Thearrangement of claim 42, wherein there is further provided a sensorarranged to communicate with the mechanical drive system for producingan information signal responsive to an operating characteristic of themechanical drive system in response to the rotatory drive force.
 49. Thearrangement of claim 48, wherein there is additionally provided furthersensor arranged to communicate with the mechanical drive system forproducing a further information signal responsive to a further operatingcharacteristic of the mechanical drive system in response to therotatory drive force.
 50. The arrangement of claim 49, wherein theoperating characteristic and the further operating characteristic of themechanical drive system correspond to drive and coast operating modes inresponse to a direction of torque of the rotatory drive force.
 51. Thearrangement of claim 48, wherein said sensor is arranged to betranslatable between a first position distal from the mechanical drivesystem, and a second position where said sensor communicates with themechanical drive system.
 52. The arrangement of claim 48, wherein saidsensor comprises a microphone responsive to an acoustic energy issued bythe mechanical drive system in response to the rotatory drive force. 53.The arrangement of claim 48, wherein said sensor comprises anaccelerometer.
 54. The arrangement of claim 48, wherein said sensorcomprises a velocity sensor.
 55. The arrangement of claim 48, whereinsaid sensor is installed on said engagement arrangement, and istranslatable therewith between the respective first and secondpositions.
 56. The arrangement of claim 48, wherein said sensorcomprises a non-contact sensor for producing a displacement signalresponsive to displacement of the mechanical drive system in response tothe rotatory drive force.
 57. The arrangement of claim 56, wherein saidnon-contact sensor comprises a laser sensor for communicating opticallywith the mechanical drive system.
 58. The arrangement of claim 48,wherein said sensor comprises a non-contact sensor for producing athermal signal responsive to a temperature of the mechanical drivesystem.
 59. The arrangement of claim 58, wherein said non-contact sensorcomprises an infrared sensor for communicating optically with themechanical drive system.
 60. The arrangement of claim 59, wherein saidinfrared sensor has a directional characteristic and is directed to apredetermined region of the energy transfer system for determining arate of change of temperature of the predetermined region with respectto time.
 61. The arrangement of claim 59, wherein there is furtherprovided an acoustic sensor sensitivity controller responsive to saidthermal sensor for varying the amplitude of a noise signal in responseto temperature.
 62. The arrangement of claim 61, wherein the response ofthe variation of the amplitude of the noise signal with respect totemperature is in accordance with a non-linear amplitude-temperaturerelationship.
 63. The arrangement of claim 42, wherein said isolationsupport comprises a resilient support element for supporting themechanical drive system, said resilient support element having aresilience frequency characteristic that excludes a natural frequency ofthe mechanical drive system.
 64. The arrangement of claim 63, whereinsaid resilience frequency characteristic of said resilient supportelement excludes a natural frequency of said drive coupler.
 65. Thearrangement of claim 42, wherein there are further provided: a rotatoryload arrangement for applying a rotatory load to the mechanical drivesystem; and a load coupler for coupling said rotatory load arrangementto the rotatory input of the mechanical drive system.
 66. Thearrangement of claim 65, wherein the mechanical drive system is adrive-transmitting component for a motor vehicle, and said rotatory loadarrangement applies a controllable rotatory load thereto to simulate aplurality of vehicle operating conditions.
 67. The arrangement of claim66, wherein the vehicle operating conditions include gear drive andcoast conditions.
 68. The arrangement of claim 66, wherein the vehicleoperating conditions include a gear float condition.
 69. The arrangementof claim 42, wherein said engagement driver comprises a linear actuatorhaving a first end for coupling to said base, and a second end forcoupling to said engagement arrangement.
 70. The arrangement of claim69, wherein there is further provided an engagement coupler interposedbetween said engagement arrangement and said engagement driver, saidengagement coupler comprising: a support portion installed on saidisolation support; first and second engagement arms pivotally coupled tosaid support portion; first and second articulated members coupled at apivot point to one another and to said linear actuator, and beingpivotally coupled at distal ends thereof to respective ones of saidfirst and second engagement arms, whereby said linear actuator urges thepivot point along a linear path to a latching position beyond where saidfirst and second articulated members are axially parallel.
 71. Thearrangement of claim 70, wherein there is further provided a resilientbiasing arrangement installed on at least one of said first and secondengagement arms for applying a resilient biasing force to the energytransfer system.
 72. The arrangement of claim 71, wherein said resilientbiasing arrangement applies a resilient biasing force that maintainssaid engagement arrangement in the second position.